"When I first came here, I thought I was going to be running an airport," Silvernell said as he steered a white sport utility vehicle along Aviation Loop Drive on a picture-perfect March day. "But I spend a lot of my time working on leasing agreements."

Not that Silvernell, who was promoted to airport director in 2003, minds his additional duties.

The joke reflects the ever-increasing role the airport has as an economic engine to drive Hernando's efforts to diversify its tax base, attract businesses and come back strong after the worst recession in a generation.

The official name, in fact, is the Hernando County Airport and Business Complex.

For Silvernell, that means a twofold mission.

The first is what takes up so much of his time. Working in partnership with the county's Office of Business Development — which shares space with the airport headquarters off Spring Hill Drive, south of Brooksville — Silvernell tries to persuade businesses to lease facilities in the complex's three main components: the 155-acre industrial park, the 80-acre corporate airpark and the 60-acre railpark.

The airport does not sell property, but tenants can build facilities to suit their needs.

Those efforts have been successful over the last decade, even as the bottom fell out of the economy. When Silvernell arrived, the complex had about 50 industrial and commercial businesses. Now there are roughly twice as many, cranking out a diverse array of products, ranging from signs to surgical motors, beer taps to industrial trash compactors. A second fixed-base operator provides aviation support services such as maintenance, repairs and fuel.

The number and diversity of the companies has helped create a "synergism" as they do business with one another, seeking services such as graphics, machining and powder coating, said county business development manager Mike McHugh.

"It's achieved its own momentum," McHugh said. "To me, it's the preeminent business complex in the north Tampa Bay region. We'd like to expand on that theme."

Continued success will rely on the other, more fundamental element of Silvernell's job description: Keep the airport running smoothly, invest in infrastructure and plan for future development.

The airport doesn't draw from or bolster county coffers. Instead, it uses revenue from leases and fuel sales along with grant funding to operate and pay for expansion.

Of last year's $2 million budget, roughly $1.4 million paid for daily operations; the rest was set aside for repairs and improvements. A host of projects are now under way or in the planning stages.

Like many airports its size throughout the country, the Hernando airport is a former Army airfield that sprouted during World War II to provide a training site for pilots and ground crews.

The first phase of the industrial park was built in the 1980s, back when most semitrailers were 35 feet long. Now trailers are typically 50 or 55 feet long, and the additional length is problematic as trucks try to make their way along the roads.

A $655,000 project is under way to widen the park's roads, especially at the turns, and to revamp swales, culverts and drainage retention areas.

Crews also have set upon the airport's two runways and primary taxiway, using jackhammers to break up and replace pitted and pitched sections of concrete. Total cost: $803,000.

The project that has garnered the most headlines is the building of a control tower.

The state is kicking in 80 percent of the $2.6 million price tag. The airport will cover the rest and maintain the tower, and the FAA will pay the annual cost to staff it. Construction could begin as early as May and will take about seven months, Silvernell said.

Some have said the tower is unnecessary, but Silvernell holds firm. The volume and diversity of air traffic is increasing, and the tower will make the airport safer, he said.

Safety can be an economic boon, too.

More corporate jet owners and pilots, spurred by the FAA, are using a checklist and points system to assess the risk of flying into certain airports. The more points, the higher the risk, and a control tower can knock off as many points as a thunderstorm sitting on top of the runway, Silvernell said.

Also, jet owners looking for a place to store their aircraft will typically find cheaper insurance rates at a tower-equipped airport than at a comparable airport without one.

These advantages will translate to more revenue in the form of hangar leases and fuel sales, Silvernell said.

A tower also will attract the attention of companies that use or service bigger jets and seek a place to set up shop. Silvernell and McHugh hope to close a deal soon with a company that maintains, repairs and overhauls jet aircraft. The operation was drawn by the airport's ability to provide a build-to-suit facility with direct airside access, McHugh said.

There are other infrastructure goals in the planning stages, though not all of the funding is in place.

A $7 million project would install the roads, water and sewers to serve an additional 10 corporate hangars.

A 175-acre second phase of the industrial park has already been designed.

The next step is to put in the roads, sewer and stormwater system, but the timetable for the roughly $2 million project got pushed back due to the recession, and it's unclear when dirt will be moved, Silvernell said.

"If the economy had kept on, we'd probably be under construction," he said.

The airport has already invested significant capital in the railpark and its spur across U.S. 41 from the main CSX line. The park is sitting mostly vacant, and that's fine, McHugh said. Rail is better for less time-sensitive, long-range freight like steel, lumber and other building materials. As the building industry rebounds, the prospect for finding long-term tenants improves.

"It's not just people swinging hammers," McHugh said, "it goes all the way up the supply chain."

Tony Marrero can be reached at tmarrero@sptimes.com or (352) 848-1431.